[opencl]

Modern xray machines deliver low enough radiation doses that they could probably be used for this reasonably safely. They are routinely used in medical settings after all, but I suspect it would still be a liability nightmare.

But there's no real need to see the bones for fitting shoes. There's plenty of 3D scanning technologies today that do not involve ionizing radiation and would probably be more useful for fitting shoes anyway.

[grahn]

Not only are there technologies that could be used for this, there are working products in the market that do it already. I work for one of the technology providers in this area.

Having x-ray images or such would actually be somewhat helpful, as you could much more easily identify the metatarsophalangeal joints (the joint where the toe meets the foot), the locations of which do influence shoe fit to some extent.

However, the cost, safety, usability etc. of using x-ray machines in a retail setting makes it infeasible by a wide margin compared to optical measurement methods, and those generally take you far enough anyway. I'd rather go for dynamic analysis (i.e. scanning the foot while it is in motion taking a step) if more data on the skeletal structure is required.